Can a 30-year-old tongue piercing earring cause a false positive on a Positron Emission Tomography (PET) scan if not removed?

Metal Tongue Piercing and PET Scan False Positives

A long-standing tongue piercing (30 years) is unlikely to cause a false positive on PET scan, but it can create imaging artifacts on the CT component that may complicate interpretation of the oral cavity and surrounding structures.

Understanding the Issue

The concern about metal jewelry and PET scans relates primarily to CT artifacts rather than false positive FDG uptake. Metal objects create beam-hardening and scatter artifacts on CT imaging, which can affect attenuation correction of the PET data and obscure adjacent structures 1.

Key Distinctions

Metal artifacts do not directly cause false positive metabolic activity, but they can:

• Create CT image distortion that affects PET attenuation correction 1
• Obscure visualization of adjacent soft tissues on the CT component 1
• Potentially lead to misregistration between PET and CT images 2

False Positive Causes on PET Scans

The actual causes of false positive FDG uptake in the oral cavity and neck region include 1:

• Infection and inflammation (the most relevant concern with piercings) - including mucositis, abscess formation, or chronic inflammatory changes 1
• Post-procedural inflammation from recent biopsies, surgery, or dental work 1
• Physiologic uptake in muscles (tongue fasciculations, muscle activity) 1
• Recent vaccinations causing lymph node uptake 1
• Granulomatous diseases like sarcoidosis or tuberculosis 1

Critical Caveat for Long-Standing Piercings

A 30-year-old piercing that is well-healed and asymptomatic should not cause inflammatory FDG uptake 1. However, if there are complications such as:

• Active infection or perichondritis (though this applies more to ear cartilage) 1
• Embedded jewelry causing chronic irritation 1
• Recent trauma or manipulation of the piercing 1

Then inflammatory uptake could theoretically occur and create a false positive interpretation 1.

Clinical Recommendation

For a well-established, asymptomatic tongue piercing:

• The metal jewelry should ideally be removed before scanning to minimize CT artifacts 1
• If removal is not possible, the interpreting physician should be informed about the piercing's presence and location 1
• The CT component should be carefully reviewed to identify artifact patterns and distinguish them from true pathology 3, 4
• Any focal uptake near the piercing site should be correlated with clinical symptoms and the CT findings 1

Interpretation Strategy

When evaluating PET scans with retained metal jewelry 1:

1. Document the presence of the metal object in the imaging report
2. Assess the CT images for beam-hardening artifacts and their extent
3. Evaluate any FDG uptake in the region for pattern (focal vs. diffuse) and intensity
4. Correlate with clinical history - specifically whether the piercing site is symptomatic
5. Consider the timing - inflammation from recent procedures is more concerning than chronic, stable findings 1

Bottom Line

A 30-year-old asymptomatic tongue piercing is very unlikely to cause false positive metabolic activity on PET scan 1. The primary concern is CT artifact affecting image quality and attenuation correction, not spurious FDG uptake 3, 4. The jewelry should be removed if possible, but if retained, careful correlation of PET findings with CT anatomy and clinical context will prevent misinterpretation 1.